Ornamental sweetpotato plant named &#39;Sweet Caroline Sweetheart Light Green&#39;

ABSTRACT

Ipomoea batatas  ‘Sweet Caroline Sweetheart Light Green’ is a very compact to compact, partially mounded cultivar producing many shoots and having dense foliage. This cultivar is distinguishable from other cultivars by small, heart-shaped, light green to chartreuse colored leaves and erect to semi-erect architecture. The plant has good vigor, is very well branched, and has thin stems that tend to intertwine. It is much less vigorous than  Ipomoea batatas  ‘Margarita’ and ‘Blackie’, and is well suited for container production. The production of flowers by ‘Sweet Caroline Sweetheart Light Green’ is rare even under short day conditions.

RELATED APPLICATION INFORMATION

This application claims the benefit of U.S. Provisional Application Ser.No. 60/752,486, filed Dec. 21, 2005; the disclosure of which isincorporated herein by reference in its entirety.

LATIN NAME OF THE GENUS AND SPECIES

The Latin name of the novel, ornamental plant variety disclosed hereinis Ipomoea batatas (L.) Lam.

VARIETY DENOMINATION

The inventive cultivar of Ipomoea batatas disclosed herein has beengiven the varietal denomination ‘Sweet Caroline Sweetheart Light Green’.

BACKGROUND OF THE INVENTION

Ipomoea species are members of the morning glory family Convolvulaceae.Ipomoea batatas, the cultivated species, is commonly produced forconsumption and referred to as the white or yellow sweetpotato and theorange yam. The plants are typically fast growing, green vinespossessing a wide variety of leaf shapes ranging from palmate and deeplylobed, to cordate or triangular shaped leaves with no lobes. Ornamentalsweetpotatoes, which have been bred and selected for their uniquefoliage colors, leaf shapes and plant habits, typically do not producelarge fleshy storage roots like the sweetpotato cultivated forconsumption. In comparison, storage roots produced by ornamentalsweetpotatoes are typically not as large because no selection has beenexercised for yield, thus storage roots do not begin to swell until verylate in the season. Further, the few storage roots that are formed byornamental sweetpotatoes are typically not as attractive as thoseproduced by the tablestock types as they are generally cracked, verymalformed, often mottled in skin and flesh color, and are not palatable.

Late in the growing season when day-lengths begin to shorten or when theplants are stressed, ornamental sweetpotato plants produce tubularflowers that are similar to morning glories, but most plantings aredominated by the appearance of the foliage. The plants are highlydesirable due to their ability to grow under varied stress conditions,cover a large space, and last the entire growing season. Moreover, theseplants have few insect or disease problems.

Until the release of the Sweet Caroline series of ornamental sweetpotatoes (see below) there were six popular types of Ipomoea batatasornamental sweetpotatoes being cultivated primarily for their annual,summer vines in landscaping applications. These six cultivars are:‘Blackie’ (not patented), having purple foliage and lavender flowers;‘Terrace Lime’ (not patented) and ‘Margarita’ (not patented; also knownas ‘Sulfur’), which have large brilliant chartreuse leaves and lavenderblooms; ‘Black Heart’ (not patented; also known as ‘Ace of Spades’),having heart-shaped leaves with burgundy purple color; ‘Tricolor’ (notpatented; also known as ‘Pink Frost’), a variegated plant having palegreen, white, and pink-margined leaves; and ‘Lady Fingers’ (unpatented),which has medium green, dainty leaves divided into long, thin,fingerlike lobes that are complemented by burgundy stems and veins.

Ipomoea batatas ‘Margarita’ was recently been released in the UnitedStates, and has become widely used as a landscape annual. However, it isnot suitable for mixed containers as this variety exhibits a veryvigorous growth and tends to out-compete other species. See Armitage. A.M. and J. M. Garner, (2001) Ipomoea batatas ‘Margarita’. Hort Science36:178. Another popular variety, ‘Blackie’, is a vigorous purple-leavedclone, which is also unsuited to containerized gardens.

Therefore, to meet the current horticultural demand, it is desirable toproduce new, more robust cultivars of ornamental sweetpotato withattractive foliage colors, leaf shapes, and plant architectures. Inaddition, it would be advantageous to develop cultivars of ornamentalsweetpotato exhibiting a more compact growth, and which do notout-compete other species in mixed containers.

Ipomoea batatas ‘Sweet Caroline Light Green’ (U.S. Plant Pat. No.15,028, issued Jul. 20, 2004), ‘Sweet Caroline Green’ (U.S. Plant Pat.No. 15,056, issued Aug. 3, 2004), ‘Sweet Caroline Bronze’ (U.S. PlantPat. No. 15,437, issued Dec. 21, 2004), ‘Sweet Caroline Purple’ (U.S.Plant Pat. No. 14,912, issued Jun. 15, 2004), and ‘Sweet Caroline Red’(United States Patent Publication No. 2006001054) are recentlyintroduced cultivars developed by the Sweetpotato Breeding and GeneticsProgram at North Carolina State University that are characterized bycompact growth habit, moderate to deeply lobed palmate leaves, andattractive foliage color.

The present invention relates to a new and distinct variety of Ipomoeabatatas named ‘Sweet Caroline Sweetheart Light Green’. ‘Sweet CarolineSweetheart Light Green’ is a very compact to compact, partially moundedvariety producing many shoots and having dense foliage. This variety isdistinguishable from other varieties by its small, heart-shaped, lightgreen to chartreuse colored leaves and erect to semi-erect architecture.The plant has good vigor, is very well branched, and has thin stems thattend to intertwine. It is much less vigorous than Ipomoea batatas‘Margarita’ and ‘Blackie’ and is well suited for container production.

Lineage. The Ipomoea batatas ‘Sweet Caroline Sweetheart Light Green’cultivar (breeding designation NC779-23NORN) originated from aconventional cross between Ipomoea batatas cultivars NC7-1ORN (thefemale parent; not patented) and NC146-1ORN (the male parent; notpatented) conducted during October 2001 to April 2002 at theHorticultural Greenhouses located at North Carolina State University,Raleigh, N.C.

NC7-1ORN was selected from seed obtained from the selfing of ‘Sulfur’.NC146-1ORN resulted from a cross between ‘Sulfur’ (the female parent)and the clone ‘S×BLR7-2’ (the male parent; not patented). ‘S×BLR7-2’ wasderived from a cross between ‘Sulfur’ (the female parent) and ‘Blackie’(the male parent). Seed from this cross were planted in theHorticultural Greenhouses in Spring 2002. The single, individual plantnow known as Ipomoea batatas ‘Sweet Caroline Sweetheart Light Green’ wasselected in August/September 2002 because of its combination ofexceptional features, and has been propagated asexually since that time.

Asexual Reproduction. Since its selection, Ipomoea batatas ‘SweetCaroline Sweetheart Light Green’ has been asexually reproduced at theHorticultural Greenhouses located at North Carolina State University,Raleigh, N.C., predominantly by vegetative propagation of vine cuttings.Successively, there have been three cycles of vegetative propagation,one cycle of tissue culture micropropagation, and multiple vegetativepropagation cycles to increase the plant population. Asexualreproduction of the new Ornamental Sweetpotato cultivar by cuttings hasshown that the unique features of the new cultivar are stable and theplant reproduces true to type in successive generations of asexualreproduction.

SUMMARY OF THE INVENTION

Ipomoea batatas ‘Sweet Caroline Sweetheart Light Green’ is a verycompact to compact, partially mounded cultivar producing many shoots andhaving dense foliage. This cultivar is distinguishable from othercultivars by small, heart-shaped, light green to chartreuse coloredleaves and erect to semi-erect architecture. The plant has good vigor,is very well branched, and has thin stems that tend to intertwine. It ismuch less vigorous than Ipomoea batatas ‘Margarita’ and ‘Blackie’, andis well suited for container production. The production of flowers by‘Sweet Caroline Sweetheart Light Green’ is rare even under short dayconditions.

BRIEF DESCRIPTION OF THE DRAWINGS

The photographs in the drawings were made using conventional techniquesand show the colors as true as reasonably possible by conventionalphotography. Colors in the photographs may differ slightly from thecolor values cited in the detailed botanical description, whichaccurately describe the colors of the new Ipomoea batatas.

FIG. 1 is a color photograph showing both new and mature foliageproduced by variety Ipomoea batatas ‘Sweet Caroline Sweetheart LightGreen’.

FIG. 2 is a color photograph showing a typical plant of the varietyIpomoea batatas ‘Sweet Caroline Sweetheart Light Green’.

FIG. 3 is a color photograph showing typical storage roots produced byIpomoea batatas ‘Sweet Caroline Sweetheart Light Green’ 123 days afterplanting. Plants were planted as five-hill plots spaced 30.5 cm apart inthe row at the Horticultural Crops Research Station, Clinton, N.C. USA.

DETAILED BOTANICAL DESCRIPTION

The following is a detailed description of the botanical characteristicsof the new and distinct cultivar of Ipomoea batatas plant known by thecultivar name ‘Sweet Caroline Sweetheart Light Green’. All colors citedherein refer to The Royal Horticultural Society Colour Chart (The RoyalHorticultural Society, London, 1995 edition) designations except wheregeneral terms of ordinary dictionary significance are used. Wheredimensions, sizes, colors, and other characteristics are given, it is tobe understood that such characteristics are approximations or averagesset forth as accurately as practicable.

The descriptions reported herein are from 11-week-old specimens. Ipomoeabatatas ‘Sweet Caroline Sweetheart Light Green’ has not been observedunder all possible environmental conditions; therefore, the phenotypemay vary under different environmental conditions such as season,temperature, light intensity, day length, cultural conditions, and thelike, without however any variance in the genotype.

Technical Description of the Variety

Above-Ground Structure. Ipomoea batatas ‘Sweet Caroline Sweetheart LightGreen’ is a very compact to compact, partially mounded cultivar. Plantheight is 20 cm and area of spread is 43 cm. It is a moderately fastgrower with good vigor. The foliage is very dense due to many leaves andresults in a round uniform plant habit.

Branching Habitat Free branching with no basal shoots.

Lateral Shoots. The number of lateral shoots varies but averages around6 with multiple short secondary shoots. Lateral branch length: ˜28 cm.Diameter: ˜0.4 cm. Internode length: ˜1.5 cm. Stems are round, smoothand sturdy without any pubescence. Shoots are initially upright but thenfall outward, forming a dense canopy. Color: bright yellow-green (RHS145B).

Petiole. Leaf petiole length varies with an average of 5.5 cm. Diameter:0.25 cm. Petiole texture is smooth. Color is 144B above and below.

Foliage. Leaves are alternate and tend to spiral around the stems. Theyare simple and heart-shaped (cordate). The number of leaves per stemvaries with length but an average stem has ˜30 leaves. The leaf tip isacuminate and the base is cordate. Leaf margins are entire and theleaves are smooth and mat with no pubescence. Leaf length averages 8.8cm (up to 11.2 cm) and leaf width averages 7.4 cm (up to 9 cm). Youngleaves are a little puckered and sinuate but flatten into decorativehearts as they mature. The venation pattern is palmate at the leaf basebecoming arcuate toward the leaf tip. Color: see Table 1. TABLE 1 LeafStructure Upper Surface Lower Surface Young Leaf Bright green, RHS 145ABright green, a little more grey than RHS 145A Mature Leaf Brightyellow-green, Bright yellow-green, RHS 144C more grey than RHS 145B Vein144C 144D

Flowers. The production of flowers by ‘Sweet Caroline Sweetheart LightGreen’ is very limited even under short day conditions.

Below-Ground Structure. Plants form no, to very small, undergroundstorage roots that are highly malformed and do not meet USDA SweetpotatoStorage Root Grade Standards (FIG. 3). Storage roots that do formtypically possess rose colored skin (186A) with a cream colored fleshthat quickly oxidizes to a light green color (191A).

Growth Conditions. Ipomoea batatas ‘Sweet Caroline Sweetheart LightGreen’ has moderate vigor and a slow to moderate growth rate. It is veryadaptable to container culture. In locales with mild winter conditions,Ipomoea batatas ‘Sweet Caroline Sweetheart Light Green’ will growperennially; otherwise it is an annual plant. Similar to cultivatedsweetpotatoes, wind or rain rarely causes much damage to ‘Sweet CarolineSweetheart Light Green’, but if damage does occur, the plant drops thedamaged leaves and grows new shoots at nodes where the leaves were lost.

Disease or Pest Resistance. Ipomoea batatas ‘Sweet Caroline SweetheartLight Green’ is susceptible to Sweetpotato Feathery Mottle Virus anddamage by Japanese beetles.

Comparison with Other Ipomoea batatas Cultivars

‘Sweet Caroline Sweetheart Light Green’ is very distinct based on leafcolor, leaf shape and plant architecture (Table 2). Of the most commoncultivars of ornamental sweetpotato, Ipomoea batatas ‘Sweet CarolineSweetheart Light Green’ is best compared with the ‘Margarita’ and‘Terrace Lime’ cultivars. Like ‘Margarita’ and ‘Terrace Lime’, Ipomoeabatatas ‘Sweet Caroline Light Green’ has light yellow-green tochartreuse leaves. However, where ‘Margarita’ and ‘Terrace Lime’ havelarge, slightly-lobed leaves, ‘Sweet Caroline Sweetheart Light Green’has small, heart-shaped leaves. Moreover, ‘Sweet Caroline SweetheartLight Green’ has a very compact to compact plant habit and strongtendency to intertwine as compared with the trailing habit of‘Margarita’.

The parental strains used to produce ‘Sweet Caroline Sweetheart LightGreen’ were NC7-1ORN (female parent) and NC146-1ORN (male parent).NC7-1ORN is a moderately vigorous, moderately compact, moderatelybranched plant with medium sized heart-shaped to slightly lobed leavesthat are light green in color. NC146-1ORN is a moderately vigorous,trailing, moderately branched plant with medium sized heart-shapedleaves that are greenish-bronze in color. TABLE 2 New Variety ‘SweetCaroline Sweetheart Light Comparison 1 Comparison 2 CharacteristicGreen’ ‘Margarita’ ‘Terrace Lime’ Plant Habit Very Compact to TrailingTrailing Compact Foliage Color Light Green to Light Green to Light Greento Yellow Yellow Yellow Leaf Size Small Moderate to Moderate to LargeLarge Leaf Shape Heart-shaped Slightly Lobed Slightly Lobed Stem VeryThin Moderately Thick Moderately Thick Thickness

Herbarium Voucher

A voucher of ‘Sweet Caroline Sweetheart Light Green’ will be depositedinto the Herbarium of North Carolina State University in Raleigh, N.C.,USA upon patenting.

1. A new and distinct cultivar of Ipomoea batatas plant named ‘SweetCaroline Sweetheart Light Green’, substantially as illustrated anddescribed herein.